Consumo, digestibilidade, balanço de nitrogênio e de água em ovino alimentados com dietas contendo níveis crescentes de taninos.

Abstract

The forage plants native to the Caatinga are an essential food resource for sheep in the Northeast, so the black jurema (Mimosa tenuiflora Wild Poir.) Appears as a food alternative for herds. It is known that tannins are found in several plant species, being a secondary compound considered as a means of defense of plants, which can be classified into condensed tannins and hydrolyzable tannins, so this tannin substance can cause influence of animal feed, which can cause beneficial effects or toxic to animals. The objective was to evaluate the effects of increasing levels of tannins on consumption, digestibility, water and nitrogen balance in sheep. 28 male Santa Inês sheep were used, with an average age of 120 days and body weight of 26.75 kg ± 2.29. The design used was completely randomized with four treatments and seven repetitions for consumption and four for digestibility and water and nitrogen balances. The optimal point for including tannins in the diet was 2.60%, 2.28% and 3.45%, respectively for SMI, NFCI and EEI. The digestibility coefficients of OM, CP, ADFap and NFC decreased to: 1.85%; 4.08%; 4.55% and 1.73%, respectively, when tannin increased (1%). For nitrogen balance there was a quadratic effect (p <0.05) for Ningested (p = 0.0031), N-Ingested Metabolic weight (p = 0.0202), N - Ex. Fecal (p = 0.0085 ), N-Feces Metabolic weight (p = 0.0189) and N - Retained (p = 0.0211). For N - Ex. Urinary (p = 0.0002), N - Absorbed (p <0.0001) there was an effect and NUrine PesoM was observed a decreasing linear effect. For free water (p = 0.0186), food water (p = 0.0046), total water intake (p = 0.0185), retained water (p = 0.0295) and metabolic water ( p = 0.0271) quadratic behavior was observed. The inclusion of 2.62% tannin in the sheep diet, from the 19.8% increase in black jurema hay, increased the intake of dry matter and total digestible nutrients. If the objective is the nitrogen balance, the inclusion level indicated is 2.4%, if the purpose is the water balance, it is recommended to include up to 5.17% tannin.